from abc import abstractmethod


class Colleague(object):
    def __init__(self):
        self.mediator = None

    def set_mediator(self, mediator):
        self.mediator = mediator

    def get_mediator(self):
        return self.mediator

    @abstractmethod
    def receive(self):
        raise ValueError('请实现方法')

    @abstractmethod
    def send(self):
        raise ValueError('请实现方法')